diff --git a/aqua/Cenon/Portfile b/aqua/Cenon/Portfile
index 2b4e7a3d49a2..4410a2e1be37 100644
--- a/aqua/Cenon/Portfile
+++ b/aqua/Cenon/Portfile
@@ -37,9 +37,10 @@ checksums           Cenon-${version}.tar.bz2 \
 
 use_bzip2           yes
 
-pre-fetch {
-    platform darwin {
-        if {${os.major} < 10} {
+platform darwin {
+    if {${os.major} < 10} {
+        known_fail  yes
+        pre-fetch {
             ui_error "${name} @${version} requires at least macOS 10.6 Snow Leopard"
             return -code error "imcompatible macOS version"
         }
diff --git a/aqua/DesktopManager/Portfile b/aqua/DesktopManager/Portfile
index 32e43c4091bc..06053be31e02 100644
--- a/aqua/DesktopManager/Portfile
+++ b/aqua/DesktopManager/Portfile
@@ -25,8 +25,9 @@ worksrcdir		${name}
 
 universal_variant no
 
-pre-fetch {
-    if {${os.major} != 8} {
+if {${os.major} != 8} {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} ${version} requires Mac OS X 10.4."
         return -code error "incompatible macOS version"
     }
diff --git a/aqua/MacBiff/Portfile b/aqua/MacBiff/Portfile
index 0454777a35cf..30346bc5ab26 100644
--- a/aqua/MacBiff/Portfile
+++ b/aqua/MacBiff/Portfile
@@ -32,8 +32,9 @@ post-patch {
     reinplace "s|__PREFIX__|${prefix}|" ${worksrcpath}/MacBiff.xcodeproj/project.pbxproj
 }
 
-pre-fetch {
-    if {${os.major} < 10} {
+if {${os.major} < 10} {
+    known_fail          yes
+    pre-fetch {
         ui_error "${name} ${version} requires Mac OS X 10.6 or greater."
         return -code error "incompatible Mac OS X version"
     }
diff --git a/aqua/iTunesMatchHelper/Portfile b/aqua/iTunesMatchHelper/Portfile
index 2d97018aa05b..846bb08e6d39 100644
--- a/aqua/iTunesMatchHelper/Portfile
+++ b/aqua/iTunesMatchHelper/Portfile
@@ -27,6 +27,7 @@ destroot {
 }
 
 if {${os.platform} eq "darwin" && ${os.major} < 11} {
+    known_fail          yes
     pre-fetch {
         ui_error "${name} ${version} requires OS X 10.7 or greater."
         return -code error "incompatible OS X version"
diff --git a/aqua/qt3-mac/Portfile b/aqua/qt3-mac/Portfile
index 0850c2aa257f..b2a20d82b15a 100644
--- a/aqua/qt3-mac/Portfile
+++ b/aqua/qt3-mac/Portfile
@@ -80,6 +80,7 @@ post-destroot {
 
 platform darwin {
     if {${os.major} > 10} {
+        known_fail  yes
         pre-fetch {
             ui_error "${name} requires Mac OS X 10.6 or older."
             return -code error "incompatible OS version"
diff --git a/aqua/xrg/Portfile b/aqua/xrg/Portfile
index fa46f9212a59..1a43109ba724 100644
--- a/aqua/xrg/Portfile
+++ b/aqua/xrg/Portfile
@@ -22,9 +22,10 @@ long_description \
     graphs on system usage.
 homepage        http://www.gauchosoft.com/Products/XRG/
 
-pre-fetch {
-    platform darwin {
-        if {${os.major} < 11} {
+platform darwin {
+    if {${os.major} < 11} {
+        known_fail  yes
+        pre-fetch {
             ui_error "${name} @${version} requires OS X 10.7 or newer."
             return -code error "incompatible OS X version"
         }
diff --git a/audio/qtplay/Portfile b/audio/qtplay/Portfile
index 5e05f316acb6..cb2de414b488 100644
--- a/audio/qtplay/Portfile
+++ b/audio/qtplay/Portfile
@@ -57,6 +57,7 @@ destroot {
 }
 
 if {${os.platform} eq "darwin" && ${os.major} > 11} {
+    known_fail          yes
     pre-fetch {
         ui_error "${name} @${version} requires OS X 10.11 or older."
         return -code error "incompatible macOS version"
diff --git a/cad/LibreCAD/Portfile b/cad/LibreCAD/Portfile
index 5040d2c099f1..05d7059adabe 100644
--- a/cad/LibreCAD/Portfile
+++ b/cad/LibreCAD/Portfile
@@ -36,8 +36,9 @@ if {${subport} eq "${name}"} {
 # see https://marc.info/?l=pkgsrc-changes&m=150505264620416&w=2
 patchfiles-append   patch-librecad-add-default-destructor-rsimage.diff
 
-pre-fetch {
-    if {${os.platform} eq "darwin" && ${os.major} < 10} {
+if {${os.platform} eq "darwin" && ${os.major} < 10} {
+    known_fail          yes
+    pre-fetch {
         ui_error "${name} ${version} requires an OS supporting qt5 to function."
         return -code error "incompatible OS X version"
     }
diff --git a/databases/postgresql7/Portfile b/databases/postgresql7/Portfile
index 508e6b6ad1fb..152603452d18 100644
--- a/databases/postgresql7/Portfile
+++ b/databases/postgresql7/Portfile
@@ -142,7 +142,8 @@ variant server description {add startup item for server} {
 }
 
 platform darwin i386 {
-	extract { return -code error "\n\nThis platform is not supported by PostgreSQL 7. Please migrate to the PostgreSQL 8 series!\n" }
+    known_fail  yes
+	pre-fetch { return -code error "\n\nThis platform is not supported by PostgreSQL 7. Please migrate to the PostgreSQL 8 series!\n" }
 }
 
 livecheck.type	none
diff --git a/devel/BWToolkit/Portfile b/devel/BWToolkit/Portfile
index 883b856c9d3d..2dca932979ef 100644
--- a/devel/BWToolkit/Portfile
+++ b/devel/BWToolkit/Portfile
@@ -22,6 +22,7 @@ hg.tag                  590c12e68e7a
 xcode.destroot.type     framework
 
 if {${os.platform} eq "darwin" && (${os.major} < 9 || ${os.major} > 10)} {
+    known_fail          yes
     pre-fetch {
         ui_error "${name} ${version} requires OS X 10.5 or 10.6 only; it does not work on earlier or later versions of OS X."
         return -code error "incompatible OS X version"
diff --git a/devel/SourceKitten/Portfile b/devel/SourceKitten/Portfile
index 214eb3bf029b..638b6104f29d 100644
--- a/devel/SourceKitten/Portfile
+++ b/devel/SourceKitten/Portfile
@@ -28,6 +28,7 @@ minimum_xcodeversions {17 10 18 10}
 
 platform darwin {
     if {${os.major} < 17} {
+        known_fail  yes
         pre-fetch {
             ui_error "SourceKitten requires 10.13 and Xcode 10 to build."
             return -code error "incompatible macOS version"
diff --git a/devel/allegro/Portfile b/devel/allegro/Portfile
index a5b0b60caca3..d4122fdfee8b 100644
--- a/devel/allegro/Portfile
+++ b/devel/allegro/Portfile
@@ -33,8 +33,9 @@ post-destroot {
     }
 }
 
-pre-fetch {
-    if {${os.platform} eq "darwin" && ${os.major} > 10} {
+if {${os.platform} eq "darwin" && ${os.major} > 10} {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} uses deprecated API which has been removed as of Mac OS X 10.7."
         return -code error "incompatible Mac OS X version"
     }
diff --git a/devel/class-dump/Portfile b/devel/class-dump/Portfile
index 26a64805b121..f6a57a1dd5ea 100644
--- a/devel/class-dump/Portfile
+++ b/devel/class-dump/Portfile
@@ -37,6 +37,7 @@ xcode.configuration Release
 xcode.destroot.path ${prefix}/bin
 
 if {${os.major} < 12} {
+    known_fail      yes
     pre-fetch {
         ui_error "${name} @${version} requires OS X 10.8 or later."
         return -code error "incompatible OS X version"
diff --git a/devel/darwinbuild-legacy/Portfile b/devel/darwinbuild-legacy/Portfile
index 611393db28e2..7391d5f670a1 100644
--- a/devel/darwinbuild-legacy/Portfile
+++ b/devel/darwinbuild-legacy/Portfile
@@ -33,8 +33,9 @@ platform darwin 9 {
 }
 
 # everything else fails, as it should
-pre-fetch {
-    if {${os.platform} eq "darwin" && ${os.major} > 9} {
+if {${os.platform} eq "darwin" && ${os.major} > 9} {
+    known_fail      yes
+    pre-fetch {
         return -code error "The ${name} port is only for Darwin 8 and 9. For Darwin\
                     10 and later, install the darwinbuild port."
     }
diff --git a/devel/darwinbuild/Portfile b/devel/darwinbuild/Portfile
index 422667c99c45..9d6422937e57 100644
--- a/devel/darwinbuild/Portfile
+++ b/devel/darwinbuild/Portfile
@@ -50,10 +50,13 @@ variant universal {
     set xcode.universal.sdk ""
 }
 
-pre-fetch {
-    if {${os.major} < 10} {
+if {${os.major} < 10} {
+    known_fail      yes
+    pre-fetch {
         return -code error "For Darwin 8 & 9 support, install the darwinbuild-legacy port."
     }
+}
+pre-fetch {
     if {![variant_isset universal]} {
         return -code error "You must install ${name} with the universal variant.\
                     Try running `port install ${name} +universal` "
diff --git a/devel/jubatus/Portfile b/devel/jubatus/Portfile
index a09eb2e3147b..683307aebd6b 100644
--- a/devel/jubatus/Portfile
+++ b/devel/jubatus/Portfile
@@ -36,6 +36,7 @@ depends_lib         port:jubatus_core \
 
 platform darwin {
     if {${os.major} <= 10} {
+        known_fail  yes
         pre-fetch {
             ui_error "$name does not build on Snow Leopard or earlier."
             error "unsupported platform"
diff --git a/devel/jubatus_core/Portfile b/devel/jubatus_core/Portfile
index c363b57cb9ea..d891263a0aca 100644
--- a/devel/jubatus_core/Portfile
+++ b/devel/jubatus_core/Portfile
@@ -27,6 +27,7 @@ depends_lib         port:msgpack \
 
 platform darwin {
     if {${os.major} <= 10} {
+        known_fail  yes
         pre-fetch {
             ui_error "$name does not build on Snow Leopard or earlier."
             error "unsupported platform"
diff --git a/devel/monotone/Portfile b/devel/monotone/Portfile
index eca4d28757af..064213e27b8b 100644
--- a/devel/monotone/Portfile
+++ b/devel/monotone/Portfile
@@ -38,6 +38,7 @@ if {${name} eq ${subport}} {
     use_bzip2           yes
     checksums           rmd160  c5e0f45028b806eb166b4aaecababa8e8e81b686 \
                         sha256  f95cf60a22d4e461bec9d0e72f5d3609c9a4576fb1cc45f553d0202ce2e38c88
+    known_fail          yes
     pre-fetch {
         return -code error "monotone port is incompatible with the current botan. Use monotone-devel instead."
     }
diff --git a/devel/nu2/Portfile b/devel/nu2/Portfile
index 41900d8afbdb..a5ceb097c6e2 100644
--- a/devel/nu2/Portfile
+++ b/devel/nu2/Portfile
@@ -38,6 +38,7 @@ depends_lib         port:libffi \
 
 platform darwin {
     if {${os.major} < 11} {
+        known_fail  yes
         pre-fetch {
             return -code error "${subport} @${version} requires OS X 10.7 Lion or later"
         }
diff --git a/devel/pficommon/Portfile b/devel/pficommon/Portfile
index dfefdef1f812..6e23cf5077ef 100644
--- a/devel/pficommon/Portfile
+++ b/devel/pficommon/Portfile
@@ -23,11 +23,13 @@ patchfiles          patch-wscript.diff
 
 platform darwin {
     if {${os.major} <= 10} {
+        known_fail  yes
         pre-fetch {
             ui_error "${name} @${version} does not build on Snow Leopard or earlier."
             error "unsupported platform"
         }
     } elseif {${os.major} >= 13} {
+        known_fail  yes
         pre-fetch {
             ui_error "${name} @${version} does not build on Mavericks or later."
             error "unsupported platform"
diff --git a/games/openrct2/Portfile b/games/openrct2/Portfile
index e4ed679928cd..1f831bc888c1 100644
--- a/games/openrct2/Portfile
+++ b/games/openrct2/Portfile
@@ -24,6 +24,7 @@ checksums           rmd160  16fe40e2a07034f8571b4020634b23f10506f39a \
 # requires 10.11 or newer at present
 # see https://trac.macports.org/ticket/55591
 if { ${os.platform} eq "darwin" && ${os.major} < 15 } {
+    known_fail      yes
     pre-fetch {
         ui_error "${name} requires OS X 10.11 or later"
         return -code error "incompatible OS version"
diff --git a/games/supertuxkart/Portfile b/games/supertuxkart/Portfile
index b0182beafc23..3d7a825dcf8d 100644
--- a/games/supertuxkart/Portfile
+++ b/games/supertuxkart/Portfile
@@ -30,6 +30,7 @@ master_sites        sourceforge:project/${name}/SuperTuxKart/${version}
 # when building with 10.7 SDK on 10.6, errors regarding missing symbols
 # are noted when running the app so that doesn't work either
 if { ${os.platform} eq "darwin" && ${os.major} < 11 } {
+    known_fail      yes
     pre-fetch {
         ui_error "${name} requires OS X 10.7 or later"
         return -code error "incompatible OS version"
diff --git a/graphics/Paintbrush/Portfile b/graphics/Paintbrush/Portfile
index 661c1f2b3373..e18503bffb9d 100644
--- a/graphics/Paintbrush/Portfile
+++ b/graphics/Paintbrush/Portfile
@@ -25,8 +25,9 @@ extract.mkdir       yes
 xcode.project       Paintbrush2.xcodeproj
 xcode.configuration Release
 
-pre-fetch {
-    if {${os.major} < 9} {
+if {${os.major} < 9} {
+    known_fail      yes
+    pre-fetch {
         return -code error "This version of ${name} is only for Mac OS X 10.5 or later."
     }
 }
diff --git a/graphics/agave/Portfile b/graphics/agave/Portfile
index 689c53ad4c82..d9da28fb45e1 100644
--- a/graphics/agave/Portfile
+++ b/graphics/agave/Portfile
@@ -59,6 +59,7 @@ post-activate   {
 
 platform darwin {
     if {${os.major} >= 13} {
+        known_fail  yes
         depends_lib
         depends_build
         pre-fetch {
diff --git a/graphics/vtk5/Portfile b/graphics/vtk5/Portfile
index 321fc99779f6..bdda49635869 100644
--- a/graphics/vtk5/Portfile
+++ b/graphics/vtk5/Portfile
@@ -128,8 +128,10 @@ variant tcltk conflicts carbon description {Build with Tcl wrappers and Tk suppo
 variant carbon conflicts x11 tcltk description {Use Carbon.  Allows embedding VTK within qt4-mac (and py*-pyqt4 when used with Python)} {
     supported_archs i386 ppc
     if {${os.platform} eq "darwin" && ${os.major} >= 12} {
-        ui_error "${name}: 'carbon' is not supported on OS X 10.8 or greater"
-        return -code error "incompatible OS X version"
+        pre-fetch {
+            ui_error "${name}: 'carbon' is not supported on OS X 10.8 or greater"
+            return -code error "incompatible OS X version"
+        }
     }
     configure.args-delete \
         -DVTK_USE_COCOA:BOOL=ON \
diff --git a/java/hadoop/Portfile b/java/hadoop/Portfile
index 9f95b90ad832..529c4de5660d 100644
--- a/java/hadoop/Portfile
+++ b/java/hadoop/Portfile
@@ -32,13 +32,16 @@ depends_lib         port:zlib \
 
 set java_home       /System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home
 
-pre-fetch {
-    # This port works on Mac OS X 10.6 or later, because 'sudo option -E'
-    # is not available on Mac OS X 10.5 or earlier. See #34665.
-    if {${os.platform} eq "darwin" && ${os.major} <= 9} {
+# This port works on Mac OS X 10.6 or later, because 'sudo option -E'
+# is not available on Mac OS X 10.5 or earlier. See #34665.
+if {${os.platform} eq "darwin" && ${os.major} <= 9} {
+    known_fail      yes
+    pre-fetch {
         ui_error "This port works on Mac OS X 10.6 (Snow Leopard) or later"
         return -code error "Mac OS X 10.6 (Snow Leopard) or later is required"
     }
+}
+pre-fetch {
     if {![file exists ${java_home}]} {
         ui_error "Java 1.6 is required, but not located at ${java_home}"
         return -code error "Java 1.6 missing"
diff --git a/java/jgoodies-common/Portfile b/java/jgoodies-common/Portfile
index 94b5adc7598a..a190767b6a75 100644
--- a/java/jgoodies-common/Portfile
+++ b/java/jgoodies-common/Portfile
@@ -23,6 +23,7 @@ use_configure           no
 worksrcdir              ${name}-${version}
 
 if {${os.platform} eq "darwin" && ${os.major} < 10} {
+    known_fail          yes
     pre-fetch {
         ui_error "${name} ${version} requires OS X 10.6 or greater for Java 6."
         return -code error "incompatible OS X version"
diff --git a/java/jgoodies-forms/Portfile b/java/jgoodies-forms/Portfile
index 76979a318ea3..46b05dab4f08 100644
--- a/java/jgoodies-forms/Portfile
+++ b/java/jgoodies-forms/Portfile
@@ -27,6 +27,7 @@ use_configure           no
 worksrcdir              ${name}-${version}
 
 if {${os.platform} eq "darwin" && ${os.major} < 10} {
+    known_fail          yes
     pre-fetch {
         ui_error "${name} ${version} requires OS X 10.6 or greater for Java 6."
         return -code error "incompatible OS X version"
diff --git a/java/jgoodies-looks/Portfile b/java/jgoodies-looks/Portfile
index 440141ed3c57..19559c96940d 100644
--- a/java/jgoodies-looks/Portfile
+++ b/java/jgoodies-looks/Portfile
@@ -26,6 +26,7 @@ use_configure           no
 worksrcdir              ${name}-${version}
 
 if {${os.platform} eq "darwin" && ${os.major} < 10} {
+    known_fail          yes
     pre-fetch {
         ui_error "${name} ${version} requires OS X 10.6 or greater for Java 6."
         return -code error "incompatible OS X version"
diff --git a/lang/apple-gcc40/Portfile b/lang/apple-gcc40/Portfile
index d3b0522cd372..8da7e9f037af 100644
--- a/lang/apple-gcc40/Portfile
+++ b/lang/apple-gcc40/Portfile
@@ -20,6 +20,7 @@ checksums           sha1    07574623e23103cb4024410ca48481fbb5da322e \
 
 platform darwin {
     if {${os.major} >= 13} {
+        known_fail  yes
         depends_lib
         depends_run
         pre-fetch {
diff --git a/lang/g95/Portfile b/lang/g95/Portfile
index 0c98d64a878c..cc772e94a85f 100644
--- a/lang/g95/Portfile
+++ b/lang/g95/Portfile
@@ -23,6 +23,7 @@ if {${os.major} < 10 || ${build_arch} eq "ppc" || ${build_arch} eq "i386"} {
 }
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail  yes
     depends_lib
     depends_run
     archive_sites
diff --git a/lang/gauche-gtk/Portfile b/lang/gauche-gtk/Portfile
index ebca02a8e7b9..eeb78d2c4477 100644
--- a/lang/gauche-gtk/Portfile
+++ b/lang/gauche-gtk/Portfile
@@ -15,6 +15,7 @@ extract.suffix	.tgz
 checksums	md5 18356efab446b9524be8371a3b852a6a
 depends_lib	port:gtk2 port:gauche
 
+known_fail  yes
 pre-fetch {
     return -code error "Sorry, this port is currently broken."
 }
diff --git a/lang/gcc10/Portfile b/lang/gcc10/Portfile
index ca06bc553bbc..8d67c1a55b49 100644
--- a/lang/gcc10/Portfile
+++ b/lang/gcc10/Portfile
@@ -149,8 +149,9 @@ use_parallel_build  yes
 destroot.target     install install-info-host
 
 # Is this gcc release supported here.
-pre-fetch {
-    if { ${os.major} < 11 } {
+if { ${os.major} < 11 } {
+    known_fail      yes
+    pre-fetch {
         ui_error "${name} ${version} is not supported on Darwin ${os.major}"
         return -code error "incompatible OS X version"
     }
diff --git a/lang/gcc43/Portfile b/lang/gcc43/Portfile
index c20cec60c7ac..40c865b36f9b 100644
--- a/lang/gcc43/Portfile
+++ b/lang/gcc43/Portfile
@@ -130,6 +130,7 @@ configure.env-append \
                     OTOOL64=${prefix}/bin/otool
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail      yes
     depends_lib
     depends_run
     archive_sites
diff --git a/lang/gcc44/Portfile b/lang/gcc44/Portfile
index d333af4d0aa2..4fa4a66d6a68 100644
--- a/lang/gcc44/Portfile
+++ b/lang/gcc44/Portfile
@@ -128,6 +128,7 @@ configure.env-append \
                     OTOOL64=${prefix}/bin/otool
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail      yes
     depends_lib
     depends_run
     archive_sites
diff --git a/lang/gcc45/Portfile b/lang/gcc45/Portfile
index f7ea1710cee5..ff4d8c17b0e4 100644
--- a/lang/gcc45/Portfile
+++ b/lang/gcc45/Portfile
@@ -150,6 +150,7 @@ configure.env-append \
                     OTOOL64=${prefix}/bin/otool
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail      yes
     depends_build
     depends_lib
     depends_run
diff --git a/lang/gcc46/Portfile b/lang/gcc46/Portfile
index 06ab43be5b45..0163cc0a4685 100644
--- a/lang/gcc46/Portfile
+++ b/lang/gcc46/Portfile
@@ -141,6 +141,7 @@ configure.env-append \
                     OTOOL64=${prefix}/bin/otool
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail      yes
     depends_lib
     depends_run
     archive_sites
diff --git a/lang/gcc47/Portfile b/lang/gcc47/Portfile
index 5e08e6d8e01a..5d97f0b9df71 100644
--- a/lang/gcc47/Portfile
+++ b/lang/gcc47/Portfile
@@ -138,6 +138,7 @@ configure.env-append \
                     OTOOL64=${prefix}/bin/otool
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail      yes
     depends_lib
     depends_run
     archive_sites
diff --git a/lang/gcc48/Portfile b/lang/gcc48/Portfile
index 68a088c69552..6a966bcc348e 100644
--- a/lang/gcc48/Portfile
+++ b/lang/gcc48/Portfile
@@ -117,6 +117,7 @@ configure.env-append \
                     OTOOL64=${prefix}/bin/otool
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail      yes
     depends_lib
     depends_run
     archive_sites
diff --git a/lang/gcc49/Portfile b/lang/gcc49/Portfile
index 8af10db5dfc7..8cbda38e2539 100644
--- a/lang/gcc49/Portfile
+++ b/lang/gcc49/Portfile
@@ -112,6 +112,7 @@ configure.env-append \
                     OTOOL64=${prefix}/bin/otool
 
 if {${os.platform} eq "darwin" && ([vercmp $xcodeversion 9.0] > 0)} {
+    known_fail      yes
     depends_lib
     depends_run
     archive_sites
diff --git a/lang/gcc5/Portfile b/lang/gcc5/Portfile
index f0f556a0e705..82e5976990bf 100644
--- a/lang/gcc5/Portfile
+++ b/lang/gcc5/Portfile
@@ -195,13 +195,14 @@ use_parallel_build  yes
 
 destroot.target     install install-info-host
 
-pre-fetch {
-    # Currently only gcc9 builds on Darwin19+. See
-    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
-    # for more background on the issue.
-    # Hopefully addressed in a future Xcode release (>11.1) but
-    # for now just error out.
-    if { ${os.major} >= 19 } {
+# Currently only gcc9 builds on Darwin19+. See
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
+# for more background on the issue.
+# Hopefully addressed in a future Xcode release (>11.1) but
+# for now just error out.
+if { ${os.major} >= 19 } {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} ${version} is (currently) not supported on Darwin ${os.major}"
         ui_error "See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835 for more details"
         ui_error "Until the issue is addressed in Xcode, please instead install gcc9 / libgcc9"
diff --git a/lang/gcc6/Portfile b/lang/gcc6/Portfile
index 2f4031c02f79..7cbf4031fcd2 100644
--- a/lang/gcc6/Portfile
+++ b/lang/gcc6/Portfile
@@ -164,13 +164,14 @@ use_parallel_build  yes
 
 destroot.target     install install-info-host
 
-pre-fetch {
-    # Currently only gcc9 builds on Darwin19+. See
-    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
-    # for more background on the issue.
-    # Hopefully addressed in a future Xcode release (>11.1) but
-    # for now just error out.
-    if { ${os.major} >= 19 } {
+# Currently only gcc9 builds on Darwin19+. See
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
+# for more background on the issue.
+# Hopefully addressed in a future Xcode release (>11.1) but
+# for now just error out.
+if { ${os.major} >= 19 } {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} ${version} is (currently) not supported on Darwin ${os.major}"
         ui_error "See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835 for more details"
         ui_error "Until the issue is addressed in Xcode, please instead install gcc9 / libgcc9"
diff --git a/lang/gcc7/Portfile b/lang/gcc7/Portfile
index cab0f674c118..521d4df7d2c6 100644
--- a/lang/gcc7/Portfile
+++ b/lang/gcc7/Portfile
@@ -172,13 +172,14 @@ use_parallel_build  yes
 
 destroot.target     install install-info-host
 
-pre-fetch {
-    # Currently only gcc9 builds on Darwin19+. See
-    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
-    # for more background on the issue.
-    # Hopefully addressed in a future Xcode release (>11.1) but
-    # for now just error out.
-    if { ${os.major} >= 19 } {
+# Currently only gcc9 builds on Darwin19+. See
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
+# for more background on the issue.
+# Hopefully addressed in a future Xcode release (>11.1) but
+# for now just error out.
+if { ${os.major} >= 19 } {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} ${version} is (currently) not supported on Darwin ${os.major}"
         ui_error "See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835 for more details"
         ui_error "Until the issue is addressed in Xcode, please instead install gcc9 / libgcc9"
diff --git a/lang/gcc8/Portfile b/lang/gcc8/Portfile
index 35a9dee81396..af06c651cab5 100644
--- a/lang/gcc8/Portfile
+++ b/lang/gcc8/Portfile
@@ -157,19 +157,23 @@ use_parallel_build  yes
 
 destroot.target     install install-info-host
 
-pre-fetch {
-    # Is this gcc release supported here.
-    # NOTE : The logic here must match that in the libgcc port.
-    if { ${os.major} < 10 } {
+# Is this gcc release supported here.
+# NOTE : The logic here must match that in the libgcc port.
+if { ${os.major} < 10 } {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} ${version} is not supported on Darwin ${os.major}"
         return -code error "incompatible OS X version"
     }
-    # Currently only gcc9 builds on Darwin19+. See
-    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
-    # for more background on the issue.
-    # Hopefully addressed in a future Xcode release (>11.1) but
-    # for now just error out.
-    if { ${os.major} >= 19 } {
+}
+# Currently only gcc9 builds on Darwin19+. See
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835
+# for more background on the issue.
+# Hopefully addressed in a future Xcode release (>11.1) but
+# for now just error out.
+if { ${os.major} >= 19 } {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} ${version} is (currently) not supported on Darwin ${os.major}"
         ui_error "See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90835 for more details"
         ui_error "Until the issue is addressed in Xcode, please instead install gcc9 / libgcc9"
diff --git a/lang/gcc9/Portfile b/lang/gcc9/Portfile
index 75be8e86e595..4a8c59ac8602 100644
--- a/lang/gcc9/Portfile
+++ b/lang/gcc9/Portfile
@@ -167,8 +167,9 @@ use_parallel_build  yes
 destroot.target     install install-info-host
 
 # Is this gcc release supported here.
-pre-fetch {
-    if { ${os.major} < 11 } {
+if { ${os.major} < 11 } {
+    known_fail  yes
+    pre-fetch {
         ui_error "${name} ${version} is not supported on Darwin ${os.major}"
         return -code error "incompatible OS X version"
     }
diff --git a/mail/pine/Portfile b/mail/pine/Portfile
index c20251c69704..3e9ec020780a 100644
--- a/mail/pine/Portfile
+++ b/mail/pine/Portfile
@@ -31,8 +31,9 @@ platform darwin 9 {
     macosx_deployment_target 10.4
 }
 
-pre-fetch {
-	if {${os.platform} eq "darwin" && ${os.major} >= 10} {
+if {${os.platform} eq "darwin" && ${os.major} >= 10} {
+    known_fail  yes
+	pre-fetch {
 		ui_error "Pine development ended with version 4.64 and evolved into the upwards-compatible replacement Alpine.  Also, this version does not build on Snow Leopard."
 		return -code error "incompatible Mac OS X version"
 	}
diff --git a/math/classias/Portfile b/math/classias/Portfile
index d1cafc174a7d..e68b1d493c49 100644
--- a/math/classias/Portfile
+++ b/math/classias/Portfile
@@ -25,6 +25,7 @@ compiler.blacklist  *clang*
 
 platform darwin {
     if {${configure.cxx_stdlib} eq "libc++"} {
+        known_fail  yes
         depends_lib
         depends_run
         pre-fetch {
diff --git a/multimedia/gpac/Portfile b/multimedia/gpac/Portfile
index dbb3d5c2f43a..c964870fcd2e 100644
--- a/multimedia/gpac/Portfile
+++ b/multimedia/gpac/Portfile
@@ -57,8 +57,9 @@ post-patch {
     reinplace "s|@APPLICATIONS_DIR@|${applications_dir}|g" ${worksrcpath}/configure
 }
 
-pre-fetch {
-    if {${os.platform} eq "darwin" && ${os.major} < 12} {
+if {${os.platform} eq "darwin" && ${os.major} < 12} {
+    known_fail  yes
+    pre-fetch {
         # See https://trac.macports.org/ticket/56408
         ui_error "${name} @${version} requires OS X 10.8 or greater."
         return -code error "incompatible Mac OS X version"
diff --git a/net/kismet/Portfile b/net/kismet/Portfile
index de09417849c0..d47a38df183a 100644
--- a/net/kismet/Portfile
+++ b/net/kismet/Portfile
@@ -34,8 +34,9 @@ patchfiles          patch-kis_panel_frontend.h.diff \
                     patch-plugintracker.h.diff \
                     patch-configure.diff
 
-pre-fetch {
-    if {${os.platform} eq "darwin" && ${os.major} > 12} {
+if {${os.platform} eq "darwin" && ${os.major} > 12} {
+    known_fail  yes
+    pre-fetch {
         return -code error "${name} is not supported on Mavericks or newer."
     }
 }
diff --git a/net/libtorrent-devel/Portfile b/net/libtorrent-devel/Portfile
index 56c45edf0b20..ae03857c3607 100644
--- a/net/libtorrent-devel/Portfile
+++ b/net/libtorrent-devel/Portfile
@@ -59,6 +59,7 @@ post-destroot {
 
 if {${os.platform} eq "darwin" && ${os.major} <= 9} {
     # currently broken, ticket #27289
+    known_fail  yes
     pre-fetch {
         return -code error "$name currently cannot be compiled on Mac OS X 10.5 or earlier."
     }
diff --git a/net/libtorrent/Portfile b/net/libtorrent/Portfile
index 151ae1962d9f..46f93a286446 100644
--- a/net/libtorrent/Portfile
+++ b/net/libtorrent/Portfile
@@ -58,6 +58,7 @@ post-destroot {
 
 if {${os.platform} eq "darwin" && ${os.major} <= 9} {
     # currently broken, ticket #27289
+    known_fail  yes
     pre-fetch {
         return -code error "$name currently cannot be compiled on Mac OS X 10.5 or earlier."
     }
diff --git a/net/libusrsctp/Portfile b/net/libusrsctp/Portfile
index 46c774e2086e..f4719460226a 100644
--- a/net/libusrsctp/Portfile
+++ b/net/libusrsctp/Portfile
@@ -22,8 +22,9 @@ master_sites        http://sctp.fh-muenster.de/download/
 checksums           sha1 b719ddd754fd21b2bda634db20640bb9477c2a1b \
                     md5  5dceb755f070ac94ae80d23686da6c91
 
-pre-fetch {
-    if {${os.platform} eq "darwin" && ${os.major} < 11} {
+if {${os.platform} eq "darwin" && ${os.major} < 11} {
+    known_fail      yes
+    pre-fetch {
         ui_error "${name} is only supported on OS X 10.7 or later."
         return -code error "unsupported platform version"
     }
diff --git a/net/mediatomb/Portfile b/net/mediatomb/Portfile
index 060bdc51bee7..aa00b8ca95b7 100644
--- a/net/mediatomb/Portfile
+++ b/net/mediatomb/Portfile
@@ -40,6 +40,7 @@ compiler.blacklist  *clang*
 
 platform darwin {
     if {${os.major} >= 13} {
+        known_fail  yes
         depends_lib
         depends_run
         pre-fetch {
diff --git a/net/rtorrent-devel/Portfile b/net/rtorrent-devel/Portfile
index c7cb0d876649..7408eb399e40 100644
--- a/net/rtorrent-devel/Portfile
+++ b/net/rtorrent-devel/Portfile
@@ -66,6 +66,7 @@ variant xmlrpc description {Enable XMLRPC interface} {
 
 if {${os.platform} eq "darwin" && ${os.major} <= 9} {
     # currently broken, ticket #27289
+    known_fail  yes
     pre-fetch {
         return -code error "$name currently cannot be compiled on Mac OS X 10.5 or earlier."
     }
diff --git a/net/tuntaposx/Portfile b/net/tuntaposx/Portfile
index 18c7256d48f8..d45090f5ef04 100644
--- a/net/tuntaposx/Portfile
+++ b/net/tuntaposx/Portfile
@@ -51,6 +51,7 @@ if {${os.major} >= 18} {
 }
 
 if { ${os.platform} eq "darwin" && ${os.major} <= 9} {
+    known_fail  yes
     pre-fetch {
         ui_error "${name} ${version} does not presently install on MacOSX 10.5 or earlier."
         return -code error "Unsupported platform"
diff --git a/security/pgp/Portfile b/security/pgp/Portfile
index ec8ea03b7a3e..0bec3e0c6f6f 100644
--- a/security/pgp/Portfile
+++ b/security/pgp/Portfile
@@ -25,6 +25,7 @@ long_description \
 patchfiles	patch-pgpFullLicense.c.diff
 
 platform darwin i386 {
+    known_fail  yes
 	pre-fetch {
 		return -code error "PGP will only build on PowerPC Macs. Try gnupg instead."
 	}
diff --git a/textproc/pialign/Portfile b/textproc/pialign/Portfile
index bf2f75f93fc3..1bcbc93dd0f4 100644
--- a/textproc/pialign/Portfile
+++ b/textproc/pialign/Portfile
@@ -32,6 +32,7 @@ compiler.blacklist  *clang*
 
 platform darwin {
     if {${os.major} >= 13} {
+        known_fail  yes
         depends_lib
         depends_run
         pre-fetch {
diff --git a/www/webkit-gtk-2.0/Portfile b/www/webkit-gtk-2.0/Portfile
index 7beb3897e575..e2a545944dc6 100644
--- a/www/webkit-gtk-2.0/Portfile
+++ b/www/webkit-gtk-2.0/Portfile
@@ -84,8 +84,9 @@ configure.args  \
         --enable-webgl
 
 platform darwin {
-    pre-configure {
-        if {${configure.cxx_stdlib} eq "libc++"} {
+    if {${configure.cxx_stdlib} eq "libc++"} {
+        known_fail  yes
+        pre-configure {
             ui_error "${name} is provided for configurations that are unable to use webkit-gtk.  Since you are on Mavericks or later (or have configured MacPorts to use libc++), please use webkit-gtk or webkit-gtk-devel instead."
             error "unsupported configuration"
         }